In voice communication of a mobile phone, a main purpose of noise suppression is to suppress environmental noises, so that a wanted voice of a mobile phone user becomes clearer. The environmental noises are classified into stationary noises and non-stationary noises. Wanted voices are generally non-stationary.
A noise suppression method includes: single-microphone (microphone) noise reduction and dual-microphone noise reduction. Single-microphone noise reduction suppresses stationary noises in environmental noises by detecting stationarity of voice signals captured by a microphone, but can hardly suppress non-stationary noises such as speech of people nearby. Dual-microphone noise reduction reduces noises by installing two microphones at specific positions in a mobile phone and using reception differences between voices and environmental noises of dual microphones. Dual-microphone noise reduction not only suppresses stationary noises desirably, but also suppresses non-stationary noises more effectively. Therefore, dual-microphone noise reduction is applied to more and more mobile phones.
The reception differences between voices and environmental noises of dual microphones include: a phase difference, an energy difference, and so on, where the energy difference is an important characteristic that is used frequently. In normal use of a mobile phone, if a microphone close to a lower part of the mobile phone is referred to as a primary microphone, and the other microphone is referred to as a secondary microphone, the energy difference is represented as follows: Because the distance between the primary microphone and a wanted voice source is different from the distance between the secondary microphone and the wanted voice source, energy of wanted voices received by the primary microphone is higher than energy of wanted voices received by the secondary microphone; because the distance between the primary microphone and a noise source is basically the same as the distance between the secondary microphone and the noise source, energy of environmental noises received by the primary microphone is basically the same as energy of environmental noises received by the secondary microphone. The energy difference may be used to distinguish wanted voice signals from environmental noises. Specifically, if energy of a same voice signal captured by the primary microphone and the secondary microphone at the same time is basically the same, the voice signal may be considered as an environmental noise; otherwise, it is considered as a wanted voice signal; further, the purpose of noise reduction is achieved by removing the environmental noise.
In a process of implementing dual-microphone noise reduction, it is found that the prior art has at least the following problems: When an energy difference between wanted voices and environmental noises received by dual microphones is used to distinguish wanted voices from environmental noises, it is required that sensitivity of the primary microphone should be strictly consistent with sensitivity of the secondary microphone. However, in an actual use process, aging, blockage, malfunction, and so on of the microphones may cause inconsistent sensitivity of the primary microphone and the secondary microphone, and further deteriorate the effect of dual-microphone noise reduction.